• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.328-334
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• 2001

The characteristics of $NO/N_2O$ nitrided oxide and reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of nonvolatile semiconductor memory(NVSM) was investigated by dynamic secondary ion mass spectrometry(D-SMS), time-of-flight secondary ion mass spectrometry(ToF-SIMS), and x-ray photoelectron spectroscopy (XPS). The specimen was annealed in $NO/N_2O$ ambient after initial oxide process. The result of D-SIMS exhibits that the center of nitrogen exists at the initial oxide interface and the distribution of nitrogen is wider in the annealing process with $N_2O$ than with NO annealing process. For investigating the condition of nitrogen that exists within the nitrided oxide, ToF-SIMS and XPS analysis were carried out. It was shown that the center of nitrogen investigated by D-SIMS was expected the SiON chemical bonds. The nitrogen near the newly formed reoxide/silicon substrate interface was appeared as $Si_2NO$ chemical bonds, and it is agreed with the distribution of SiN and $Si_2NO$ species by ToF-SIMS.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.91-94
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• 2008

Newly developed Atom Probe Tomography (APT) technique can provide the highest available spatial resolution, 3D tomography imaging and quantitative chemical analysis in a sub-nm scale. As a complementary technique to APT, Nano-secondary ion Mass Spectroscopy (SIMS) also provides the boron distribution in micro-scale. Therefore, the exact behavior of boron at either grain boundary or grain interior in steels can be investigated by the combination of APT and SIMS techniques from the sub-nanometer scale to the micrometer scale. The results obtained by both APT and SIMS revealed that the boron atoms were mainly segregated to the grain boundaries rather than to the grain interior in the steels containing 50ppm and 100ppm boron. It also found that carbon atoms were segregated at the boron enriched regions, which were thought to be retained austenite phase due to the chemical composition of carbon atoms.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.203-214
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• 2015

We have been developing a new label-free nanobio imaging platform using non-linear optics such as Coherent Anti-Stokes Raman Spectroscopy (CARS) and ion beam techniques based on sputtering and scattering such as Secondary Ion Mass Spectrometry (SIMS) and Medium Energy Ion Scattering Spectroscopy (MEIS), which have been widely used for atomic and molecular level analysis of semiconductors and nanomaterials. To apply techniques developed for semiconductors and nanomaterials for biomedical applications, the convergence of nano-analysis and biology were tried. Our activities on label-free nanobio imaging during the last decade are summarized in this review about non-linear optical 3D imaging, ellipsometric interface imaging, SIMS imaging, and TOF-MEIS nano analysis for cardiovascular tissues, collagen thin films, peptides on microarray, nanoparticles, and cell adhesion studies and finally the present snapshot of nanobio imaging and the future prospect are described.

• Korean Journal of Materials Research
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• v.23 no.10
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• pp.555-561
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• 2013

The hardenability of low-carbon boron steels with different molybdenum and chromium contents was investigated using dilatometry, microstructural observations and secondary ion mass spectroscopy (SIMS), and then discussed in terms of the segregation and precipitation behaviors of boron. The hardenability was quantitatively evaluated by a critical cooling rate obtained from the hardness distribution plotted as a function of cooling rate. It was found that the molybdenum addition was more effective than the chromium addition to increase the hardenability of boron steels, in contrast to boron-free steels. The addition of 0.2 wt.% molybdenum completely suppressed the formation of eutectoid ferrite, even at the slow cooling rate of $0.2^{\circ}C/s$, while the addition of 0.5 wt.% chromium did this at cooling rates above $3^{\circ}C/s$. The SIMS analysis results to observe the boron distribution at the austenite grain boundaries confirmed that the addition of 0.2 wt.% molybdenum effectively increased the hardenability of boron steels, as the boron atoms were significantly segregated to the austenite grain boundaries without the precipitation of borocarbide, thus retarding the austenite-to-ferrite transformation compared to the addition of 0.5 wt.% chromium. On the other hand, the synergistic effect of molybdenum and boron on the hardenability of boron steels could be explained from thermodynamic and kinetic perspectives.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.576-582
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• 2002

Nonvolatile semiconductor memory devices with reoxidized nitrided oxide(RONO) gate dielectrics were fabricated, and nitrogen distribution and bonding species which contribute to memory characteristics were analyzed. Also, memory characteristics of devices depending on the anneal temperatures were investigated. The devices were fabricated by retrograde twin well CMOS processes with $0.35\mu m$ design rule. The processes could be simple by in-situ process in growing dielectric. The nitrogen distribution and bonding states of gate dielectrics were investigated by Dynamic Secondary Ion Mass Spectrometry(D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry(ToF-SIMS), and X-ray Photoelectron Spectroscopy(XPS). As the nitridation temperature increased, nitrogen concentration increased linearly, and more time was required to form the same reoxidized layer thickness. ToF-SIMS results showed that SiON species were detected at the initial oxide interface which had formed after NO annealing and $Si_2NO$ species within the reoxidized layer formed after reoxidation. As the anneal temperatures increased, the device showed worse retention and degradation properties. It could be said that nitrogen concentration near initial interface is limited to a certain quantity, so the excess nitrogen is redistributed within reoxidized layer and contribute to electron trap generation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.224-230
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• 2001

The characteristics of $NO/N_2O$ annealed reoxidized nitrided oxide being studied as super thin gate oxide and gate dielectric layers of Non-Volatile Semiconductor Memory (NVSM) were investigated by Dynamic Secondary Ion Mass Spectrometry (D-SIMS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and Auger Electron Spectroscopy (AES). The specimen was annealed by $NO/N_2O$ after initial oxide process and then rcoxidized for nitrogen redistribution in nitrided oxide. Out-diffusion of incorporated nitrogen during the wet oxidation in reoxidation process took place more strongly than that of the dry oxidation. It seems to indicate that hydrogen plays a role in breaking the Si N bonds. As reoxidation proceeds, incorporated nitrogen of $NO/N_2O$ annealed nitrided oxide is obsen-ed to diffuse toward the surface and substrate at the same time. ToF-SIMS results show that SiON species are detected at the initialoxide interface, and Si,NO species near the new $Si_2NO$ interface that formed after reoxidation. These SiON and $Si_2NO$ species most likely to relate to the origin of the state of memory charge traps in reoxidized nitrided oxide, because nitrogen dangling bonds of SiON and silicon dangling bonds of $Si_2NO$ are contained defects associated with memory effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.959-964
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• 2001

We investigated the etching characteristics of YMnO$_3$ thin films in high-density plasma etching system. In this study, YMnO$_3$ thin films were etched with CF$_4$/Ar gas chemistries in inductively coupled plasma(ICP). Etch rates of YMnO$_3$ increased up to 20% CF$_4$ in CF$_4$/(CF$_4$+Ar), but decreased with furthermore increasing CF$_4$ in CF$_4$/(CF$_4$+Ar). In optical emission spectroscopy (OES) analysis, F radical and Ar* ions in plasma at various gas chemistries decreased with increasing CF$_4$ content. Chemical states of YMnO$_3$ films exposed in plasma were investigated with x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). There is a chemical reaction between metal (Y, Mn) and F and metal-fluorides were removed effectively by Ar ion sputtering. YF$_{x}$, MnF$_{x}$ such as YF, YF$_2$, YF$_3$ and MnF$_3$ were detected using SIMS analysis. The etch slope is about 65$^{\circ}$ and cleasn surface. surface of the etched YMnO$_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The etch profile was also investigated by scanning electron microscopy (SEM).EM).

• Korean Journal of Materials Research
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• v.11 no.1
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• pp.55-60
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• 2001

The effect of high energy B ion implantation and initial oxygen concentration upon defect formation and gettering of metallic impurities in Czochralski silicon wafer has been studied by applying DLTS( Deep Level Transient Spectroscopy), SIMS(Secondary ton Mass Spectroscopy), BMD (Bulk Micro-Defect) analysis and TEM(Transmission Electron Microscopy). DLTS results show the signal of the deep levels not only in as-implanted samples but also in low and high temperature annealed samples. Vacancy-related deep levels in as- implanted samples were changed to metallic impurities-related deep levels with increase of annealing temperature. In the case of high temperature anneal, by showing the lower deep level concentration with increase of initial oxygen concentration, high initial oxygen concentration seems to be more effective compared with the lower initial oxygen one.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.17-20
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• 2001

Nonvolatile semiconductor memory devices with reoxidized nitrided oxide(RONO) gate dielectric were fabricated, and nitrogen distribution and bonding species which contributing memory characteristics were analyzed. Also, memory characteristics of devices according to anneal temperatures were investigated. The devices were fabricated by 0.35$\mu\textrm{m}$ retrograde twin well CMOS processes. The processes could be simple by in-situ process of nitridation anneal and reoxidation. The nitrogen distribution and bonding state of gate dielectric were investigated by Dynamic Secondary Ion Mass Spectrometry(D-SIMS), Time-of-Flight Secondary ton Mass Spectrometry(ToF-SIMS), and X-ray Photoelectron Spectroscopy(XPS). Nitrogen concentrations are proportional to nitridation anneal temperatures and the more time was required to form the same reoxidized layer thickness. ToF-SIMS results show that SiON species are detected at the initial oxide interface and Si$_2$NO species near the new Si-SiO$_2$ interface that formed after reoxidation. As the anneal temperatures increased, the device showed worse retention and degradation properties. These could be said that nitrogen concentration near initial interface is limited to a certain quantity, so excess nitrogen are redistributed near the Si-SiO$_2$ interface and contributed to electron trap generation.

• Journal of the Korean Vacuum Society
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• v.4 no.1
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• pp.104-108
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• 1995

Hall 효과 측정을 이용하여 As+이 주입된 다결정 실리콘의 열처리 조건에 따른 활성화 과정을 연구하였다. 주입된 이온의 농도 분포는 SIMS(Secondary Ion Mass Spectroscopy)와 SUPREMIV 모의 실험으로 조사하였다. 열처리 온도가 증가함에 따라 활성층의 전자 면 농도 증가가 뚜렷이 나타났으며, Hall 이동도의 온도 의존성 측정으로 주입된 도우즈에 따라 이온 주입층의 활성화에 필요한 열처리 온도가 달라져야함을 알 수 있었다. 그리고, 접합 손실전류의 감소는 $800^{\circ}C$(30분)의 열처리에서 현저하게 나타났다.